Monoazo chromium complex



Patented Nov. 8, 1949 MQNQAZQGH-ROMIUM COMPLEX Harry W. Grimmel', Providencd lt. I., and',Ludwig Richter; Easton Pa., assi'g-norsto General? Aniline. & Film- G'orporation, NiewYork, N. Y'., a corporation of Delaware,

No Drawing. Application. All-gust; 11,, 194%,,

Serial No. 44,408

1 Claim.

This invention relates to, the production of azo dye compounds. and. their application to the art of dyeing or coloring. More particularly, it relates to a monoazo dye capable of being converted into its metal complex compounds by the monochrome or metachrome, process as well as the aftercme. p cess- In the dyeing of woolen fabrics by one or another of the mord'anting. processes, such as chrome mordantina, p-chrome, aiten hromi s, an monochrome or metachrome processeswhichare commonly employed in the fixing of acid" dyes onto the fabrics, it is highly desirable that the dyesbe-such that they do,n,ot, stain acetate eiiects he. fibers. Many dyes,. particularly azo dyes, have been, developed which. are suitablefor the after-chroming process and some have been produced which are suitable for the monochrome or metachrome mordanting process. However, few give good results in both processes. In the mono chrome or metachrome process, the azo dye is metallized and precipitated on the fiber simultaneously by adding to the dye bath a mixture of an alkali metal chromate and an ammonium salt, such as ammonium sulfate. When the dye liquor is boiled, ammonia is gradually evolved and sulfuric acid formed in the dye bath which at once converts the chromate present into the bichromate. This acts on the dyestuff and fixes it on the fiber as the chrome lake. mixture is added to the dye bath, no precipitation takes place so that it is possible to dye in one bath. However, if the bichromate is added to the dye bath along with the dyestuii, immediate precipitation of the dyestuff generally takes place. 1

Many dyestuffs are precipitated even by the chromate so that this process is necessarily limited in its application.

Among those dyes which are said to be suitable for the monochrome or metachrome process is the monoazo dye obtained from diazotized 4-nitro-2- aminophenol coupled with N-phthaloylamido hydroxynaphthalene. This dye is described in U. S. Patent 1,411,245 and it is said that, when this dye is dyed in the presence of an alkali metal chromate and an ammonium salt, such as ammonium sulfate, it will furnish on wool olive tints of an excellent fastness to milling. It has been discovered, however, that the olive tints produced by this dye are of an unattractive dull shade which has a poor evening color, that is, when viewed under artificial light it has a different shade than when viewed under natural light. When dyeing wool fabrics having acetate effects, it has further been discovered that this dye stains When the chromate the acetate efi-ectzfibers a very heavy violet color and also that when dyed by the atter-chroming process rather than the monochrome process described in the patent; it yields only very weak shades of a greenishrgray color, apparently due to the fact that the dye is not stable to the oxidizing influenceof. the bic'hromate used in the afterchroming bath.

In our co-pending application Serial Number 628,658, filed November 14, 1945, now Patent No. 2,459,813, there; is described a monoazo dyge; produped! from diazotized a-nitro-zi-aminophenol-fis li c c d and theN nhthalcylam dc hydn xynaphthalenecqun i s s mpo cnt f he cwins truc llm ITTlEL-C O- which, when converted in substance or on the fiber by any of the common metallizing processes into its metal complex compounds, produces dyeings of outstanding properties. We have also found that the monoazo dye produced from the isomeric 6-nitro-Z-aminophenol--sulfonic acid and the same N-phthaloylamido hydroxynaphthalene coupling component has similarly distinctive properties. The isomeric dye produces a green-gray shade when applied to wool by the monochrome process, that is, by fixing the unmetallized dye on the fabric in the presence of an alkali metal chromate and an ammonium salt such as ammonium sulfate. When treated by the after-chrome process the 6-nitro-2-aminophenoll-sulfonic acid azo dye produces a very deep oliveblack shade. In both cases the shade produced is more neutral and is influenced more by the blue than the yellow than in the case of the monochrome and after-chrome effects produced from the 4-nitro-2-aminophenol-6-sulfonic acid isomer when using the same N-phthaloylamido hydroxynaphthalene coupling component.

Our new azo dye derived from the diazotized 6-nitro-2-aminophenoll-sulfonic acid in its method, the following example is given, the parts being by weight unless otherwise specified.

Example 33.9 grams G-nitro-Z-aminophenol--sulfbnic acid 100% is diazotized in the usual way at 0 C.

and combined with a solution of 45.8 grams- 1-phthaloylamido-7-hydr0xynaphthalene 100 M. W. 30'? in. 200 ml. water, 15 ml. NaOI-I solution (40% by weight) and 150 cc. of a 20% soda ash 1 OH OH lhe dye which is thus obtained dissolves easily in water and yields when dyed on wool by the direct method a black dye which by after-chroming turns to a powerful olive-black. When the dye is dyed on wool according to the monochrome process of metachrome mordant process, a bright green shade having excellent fastness 'to light, crocking and fulling is obtained, which shade does not change to any appreciable extent when viewed under artificial light. The olive-black shade obtained by the after-chroming process, when using this dye, also possesses these same good dyeing properties and as indicated above, does not stain acetate fiber effects.

Having now fully described our invention and having illustrated it by a specific example, clearly setting forth the best manner in which to perform it, what we claim as new is:

The chromium complex compound of the monoazo dye having the following structural formula:

HARRY W. GRIMMEL. LUDWIG RICHTER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,411,245 Geldermann et a1. Mar. 28, 1922 1,925,434 Clingestein et a1. Sept. 5, 1933 

